The present invention relates to liquid level controls and, more particularly, to a system for pumping excess water from a swimming pool which employs a hydraulic control mechanism.
Swimming pools are designed to operate most effectively when the water level in the pool is maintained at a predetermined level. A gutter surrounds the water and a skimmer mechanism aspirates water from the gutter, through a coarse filter and into the main filter/recirculating system. When the water level is correctly maintained, this mechanism effectively removes leaves, insects and floating debris from the pool. After a rainfall, the water level may be so high that the floating debris is no longer removed by this skimmer mechanism. It will then be a task to pump out the excess water and clean any clinging debris off the pool walls. Electrically operated level control devices are well known in the art. A float switch at the pool applies electric power to a pump or to an electrically actuated valve when the level gets high so that water is pumped to a drain until a predetermined level is reached. Several problems are presented by these devices. When the pool is in use, the level will rise from displacement and water motion from activity will trigger drainage of water erroneously that must later be added and the pool will be too low for proper skimming. The system may then be adding and draining water continuously. Furthermore, electric current at or near the pool is a shock hazard, and electric switch contacts in the corrosive chlorine environment are trouble prone.